An Illinois Tollway committee on Wednesday approved nearly $170 million for engineering consulting contracts to prepare for work to rebuild and widen the Jane Addams Memorial Tollway and build the new Elgin-O'Hare West Bypass.

The largest single contract, $66.8 million, would go to Colorado-based CH2M HILL Inc., for corridor management and design services for the proposed O'Hare project.

All the contracts need final approval from the tollway board, which meets April 26.

The engineers will design the road projects and oversee the work of other engineers and construction firms. Construction contracts are expected to be awarded next year, tollway Chief Engineer Paul Kovacs said.

"They're going to help manage all those different pieces so that we can make sure they're all working together effectively," Kovacs said.

The bypass will be a new tollway on the airport's western edge, linking the Tri-State Tollway (Interstate 294) on the south and the Addams (I-90) on the north.

The existing Elgin-O'Hare Expressway would be extended east from I-290 along Thorndale Avenue to the bypass.

The tollway included the project in its 15-year, $12.1 billion capital program approved last August. The near-doubling of tolls that went into effect Jan. 1 will pay for the work.

The Elgin-O'Hare project is expected to cost $3.4 billion, most of it coming from the tollway. About $300 million remains unfunded and is expected to come from local communities.

Some initial work could start in 2013, officials said.

The tollway committee also approved contracts totaling over $102 million for engineering and design work on the Addams reconstruction and widening.